Random access memory (MRAM) cells using a thermally assisted write operation usually comprise a magnetic tunnel junction formed from a reference layer having a fixed magnetization, a storage layer having a magnetization that can be switched and a tunnel barrier between the reference and storage layers. The MRAM cell further comprises an antiferromagnetic layer exchange-coupling the magnetization of the storage layer. Such MRAM cells are characterized by a considerably improved thermal stability of the storage layer due to the exchange-coupling of the antiferromagnetic layer. An improved writing selectivity of such MRAM cells is also achieved due to the selective heating of the memory cell to be written in comparison with the neighboring memory cells remaining at ambient temperature. The MRAM cell is written using a field current passing in a field line such as to generate a magnetic field adapted to switch the magnetization of the storage layer when the memory cell is heated. The magnitude of the field current can be however too high for low power applications.